Modular Bridge

ABSTRACT

The description relates to modular bridges. On example of a modular bridge includes multiple parallel longitudinal modules. An individual module includes a steel superstructure embedded in a concrete deck that includes a longitudinal keyway. The concrete deck serves to maintain a longitudinal camber of the steel superstructure rather than diminishing the longitudinal camber. Adjacent parallel longitudinal modules are bolted together at adjacent opposing longitudinal keyways.

PRIORITY

This utility patent application claims priority from U.S. Provisional Patent Application 61/534,808, filed on Sep. 14, 2011 and from U.S. Provisional Patent Application 61/593,538, filed on Feb. 1, 2012, which are hereby incorporated by reference in their entirety.

BACKGROUND

Traditionally, bridges have been constructed piece by piece on site. This technique tends to be slow and costly.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings illustrate implementations of the concepts conveyed in the present application. Features of the illustrated implementations can be more readily understood by reference to the following description taken in conjunction with the accompanying drawings. Like reference numbers in the various drawings are used wherever feasible to indicate like elements. Further, the left-most numeral of each reference number conveys the Figure and associated discussion where the reference number is first introduced.

FIGS. 1 and 3 show elevational views of modular bridges in accordance with some implementations of the present concepts.

FIGS. 2 and 4 show sectional views of the modular bridges of FIGS. 1 and 3, respectively, in accordance with some implementations of the present concepts.

FIGS. 5-8 show isometric views of bridge modules in accordance with some implementations of the present concepts.

FIGS. 9-14, 16, and 18 show sectional views of elements of modular bridges in accordance with some implementations of the present concepts.

FIGS. 15 and 17 show elevational views of elements of modular bridges in accordance with some implementations of the present concepts.

DETAILED DESCRIPTION Overview

The present description relates to a modular bridge (or bridge). The bridge can be pre-fabricated in bridge modules (or modules). The modules can be manufactured in a controlled environment such as a workshop. In some implementations, the modules can be fabricated from steel and concrete to leverage the beneficial properties thereof. For instance, the modules can include a steel superstructure that is partially encompassed in concrete and has a concrete road or deck surface formed thereon and includes a steel guard rail. In some implementations individual modules can span the entire length of the bridge. For instance, a four lane bridge may be comprised of four modules where each module is about the width of a lane. The modules can be shipped to the bridge site completely ready to go (e.g., able to provide a drivable or accessible structure). The modules can be positioned on supports, such as abutments and piers, and fastened together. Once fastened together, the bridge can be complete and ready to use. In this example the modules are the width of the lanes, however, such need not be the case. For instance, a two lane bridge may be constructed from three parallel modules or a four lane bridge constructed from five parallel modules. In other configurations, individual modules may not span the entire length of the bridge. In such a case, modules may be placed end-to-end and fastened together to span the overall length. These modules can then be fastened to adjacent modules to provide the desired width of the bridge. For example, the keyway techniques described in this document could be applied to the lateral joints between consecutive modules.

In other implementations, the modules can be cast in place to reduce module weight during transportation. In the cast in place configuration, the concrete can be poured on site. This module could have the structural supports, decking for the stay in place form, and the rebar attached before it is shipped to the site.

In construction, modules can be defined as a bundle of redundant project components. The modules can be produced en-masse prior to installation or on-site. The present discussion defines a module as a longitudinal bridge section. Multiple modules can be employed in a given bridge. In some cases, the modules can be arranged in a co-extensive fashion such that each module runs the length of the bridge and contributes a portion of the width of the bridge. The modules can be designed to comply with shipping and weight limitations (for a given road or travel route) to be delivered and placed on site. In some implementations, the modules can be shop produced as a finished product with reduced (and/or minimal) field work employed on-site.

First Implementation

FIGS. 1-2 collectively illustrate one implementation of a bridge system 100. In some implementations a bridge system can be thought of as including several components starting with a bridge 102. FIG. 1 shows a view along a longitudinal axis of the bridge (e.g., parallel the y-reference axis). FIG. 2 shows a view taken orthogonally to the longitudinal axis (e.g., transverse the y-reference axis). The bridge 102 can provide a deck surface or riding surface 104 over which people and/or vehicles can travel without regard to the underlying topography.

The bridge 102 can be interposed between bridge abutments or footings 106(1) and 106(2). The bridge 102 can be set on top of the bridge abutments 106(1) and 106(2). Some implementations can employ piers (not shown) along the bridge. For example where the bridge spans a relatively large distance, the piers can be employed as supports that can be used to break up a long span. The piers can be located intermittently between the abutments for support and the bridge can be set on top of a pier just like an abutment. A backwall 110 can be used to backfill up against the approach to the bridge deck. The backwall 110 can be located at the abutments and it can extend from the top of the abutment to the bottom of the bridge deck. A rail (guardrail or handrail) or barricade 112 can be located on the lateral edges of the bridge 102.

In the present implementations, the bridge can be formed from modules 114. This example includes four modules 114(1)-114(4). The modules 114 can collectively provide the riding surface or deck surface 104 which can define a width of the bridge. In this case, the modules can be described as including a superstructure 116 and a bridge deck 118. For example, module 114(1) includes superstructure 116(1) and bridge deck 118(1). Similarly, module 114(2) includes superstructure 116(2) and bridge deck 118(2). (Reference to these elements with the use of a suffix (e.g., “(1)” or “(2)”) is intended to be specific to an individual instance of that element. Reference without the suffix is intended to be generic to the element).

Taken collectively, the bridge decks 118(1)-118(4) provide the riding surface 104 (e.g., the upward facing generally horizontal surface of the bridge deck). Most implementations utilize concrete as the bridge deck 118. However, other deck materials that can be applied in a relatively manipulatable form and subsequently harden into a relatively rigid form could alternatively be used. The superstructure 116 can support the bridge deck 118. In this implementation each superstructure 116 includes multiple girders. For instance, superstructure 116(1) includes first and second girders 120(1) and 122(1) and superstructure 116(2) includes first and second girders 120(2) and 122(2). The term “girder” can include steel or iron beams or compound structures (e.g., trusses).

In this case, the first and second girders 120 and 122 of an individual module 114 are cross-braced as indicated at 124 (the cross-bracing is only specifically designated relative to superstructure 116(1) to avoid clutter on the drawing page). Other types of superstructures are described below relative to FIGS. 3-7. FIGS. 3-7 also show a configuration that employs a single superstructure (e.g., girder) per module. Such a configuration can producer lighter modules and/or be more cost effective than employing multiple superstructures per modules, in some instances.

Adjacent modules 114 (e.g., module 114(1) and 114(2) or module 114(2) and 114(3)) can be fastened together utilizing longitudinal keyways 126 (not all of which are designated with specificity). External modules 114(1) and 114(4) include a single keyway (e.g., on their respective internal facing vertical longitudinal edge). Internal modules 114(2) and 114(3) include keyways on each of their respective opposing longitudinal vertical edges. For instance, module 114(1) includes keyway 126(1) and module 114(2) includes keyways 126(2) and 126(3). Keyways 126(1) and 126(2) can be fastened together with hardware at the bridge site to interconnect the adjacent modules. Keyways are described in more detail below relative to FIGS. 5-18.

For ease of explanation, the superstructure 116 and the bridge deck 118 are introduced above as separate components or elements. However, as should become apparent from the description below, the superstructure 116 and the bridge deck 118 of an individual module 114 can offer advantages greater than those offered by the elements taken in isolation. In this case, the superstructure 116 is embedded into, and bonds with, the bridge deck 118. The resultant module offers several advantages over present technologies. First, in this system the bridge deck is not simply dead load on the superstructure. Instead, the bridge deck contributes to the strength of the module. Viewed from one perspective, the steel superstructure embedded in the concrete bridge deck leverages and augments the beneficial properties of each element. The steel superstructure offers a high strength to weight ratio. The concrete bridge deck provides a high friction driving surface for the bridge and the rigidity of the concrete bridge deck contributes to maintaining the camber of the steel superstructure (thereby increasing its load carrying capacity). Second, forming the bridge deck 118 onto the superstructure 116 of the individual module 114 offers flexibility in the construction process. For example, this reduces or alleviates the need for a field concrete pour. This may save on the field costs of the concrete pour. Further, the modules can be manufactured off-site, such as in a shop or other controlled environment. Further still, the present concepts eliminate the need for tensioning (either during the concrete pour or after) of the concrete of the bridge deck. This aspect can greatly simplify construction. Alternatively or additionally, the combined superstructure and the bridge deck of the bridge module can provide a huge time savings to the project. These aspects are described in more detail below.

Second Implementation

FIGS. 3-4 introduce another bridge 302 that is similar to bridge 102 described above. For sake of brevity not all of the elements introduced relative to bridge 102 are re-introduced here. Instead the above designators are maintained where practicable except that the leftmost numeral is changed from “1” to “3”. Of note, bridge 302 includes six bridge modules 314(1)-314(6) rather than the four bridge modules of bridge 102. Further, the superstructure 316 of individual modules includes a single girder 320 rather than two girders of the above described implementation.

The following discussion includes more detail relating to bridge modules and techniques for constructing bridge modules consistent with some implementations. This description is explained relative to modules 314, but is applicable to other modules as well. Elements are introduced in the first part of the discussion and then the function of the elements is discussed relative to an overall bridge construction description under the heading “EXAMPLE PROCESS.”

FIGS. 5-8 collectively show module 314(1) in greater detail as well as how to build such modules in accordance with some implementations. FIGS. 5 and 6 are generally complementary views from above and below the module, respectively. FIGS. 5 and 6 show an end length of a bridge deck form 502 built around girder 320(1). FIG. 7 shows a view from above a running length of form 502. FIG. 8 shows more detail of the side of the form 502.

FIG. 5 is a partial cut-away view in that a first portion 504 shows concrete 500 of bridge deck 318(1) in place in the form 502, whereas a second portion 506 does not show the concrete so that the underlying elements can be visualized. Note also, that this implementation features a departure angle α of 45 degrees rather than the more typical right angle departure (represented by dotted arrow 508) at the bridge abutment. The present module formation techniques readily adapt to variations from typical configurations.

In this case the form 502 includes side forms 510, end forms 512, keyway forms 514, and a sheet material 516. The side forms 510, end forms 512, and keyway forms 514, can be formed from any material, such as dimensional lumber or tube steel that can provide structural strength to the form. Similarly, the sheet material 516 serves as a base for the poured concrete of the bridge deck 318(1). The sheet material can be manifest as plywood, oriented strand board, sheet metal, and/or dimensional lumber, among others. The form is configured such that a top horizontal surface 518 of girder 320(1) can function as part of the form (or can be contained within the form). Further, structures are secured to the girder 320(1) to increase bonding between the girder and the concrete of the bridge deck 318(1). In this case, the structures are manifest as a plurality of headed or flared anchor studs 520 which are secured to the girder 320(1) and are embedded in the concrete 500.

The anchor studs 520 can be welded to the girder 320(1). Alternatively, the anchor studs can be manifest as bolts which are screwed into the girder or fastened to the girder with a nut positioned on the underside of the upper horizontal portion of the girder. Embedding portions of the girder 320(1) and/or the anchor studs 520 in the concrete 500 of the bridge deck 318(1) in this manner can serve to create a unified structure (e.g., module) from the bridge deck and the girder that can have different (e.g., better) properties than the two elements in isolation.

In the illustrated configuration, two rows of anchor studs 520 are arranged longitudinally along the girder 320(1). Other implementations could use a single row, more than two rows, or could place the anchor studs 520 in some other pattern. The anchor studs 520 can be arranged at a uniform distance along the length of the girder. Alternatively in the illustrated configuration, the anchor studs occur more frequently near the ends of the girder 320(1) than in the middle of the girder. For example, in this case each row of anchor studs includes two anchor studs per foot at the ends of the girder whereas the middle 70 percent of the girder includes one anchor stud per foot per row. Forces, such as shear forces, between the bridge deck 318(1) and the superstructure 316(1) tend to be relatively higher at the ends of the module 314(1) than in the middle. Increasing the density of the anchor studs 520 at the ends of the girder 320(1) can increase bonding between the girder and the bridge deck at these high stress areas. The above description details several useful examples for bonding the bridge deck and the superstructure, of course, the present concepts cover other implementations. For example, other structures for increasing the bonding between the concrete 500 and the girder 320(1) are contemplated. Further, the dimensions provided in the above examples are provided for purposes of explanation and are not intended to be limiting in any way.

Various other elements are also shown relative to form 502. For instance, these elements include rebar 522, blockouts 524, rail connections or rail brackets 526, keyway channel 528, abutments 530, diaphragm brace 602 (FIG. 6), adjustable stand 604 (FIG. 6), outrigger 606 (FIG. 6), support bracket 608 (FIG. 6), connector 610 (FIG. 6), support members 612 (FIG. 6), blocking points 614 (FIG. 6) and lifting lugs 702 (FIG. 7). These elements are introduced briefly here and are discussed in more detail below. The function of the elements is also explained in context in the section heading “Example Process.”

Rebar 522 is positioned in the form 502 to add strength to the deck concrete. In this case, longitudinally oriented rebar is shown. Laterally oriented rebar is described below relative to FIG. 7.

Blockouts 524 can facilitate field casting backwall 310 (FIG. 3). Rail brackets 526 allow for various types of rails, such as guard rails or hand rails, to be secured to the module.

Keyway channel 528 can contribute to forming the keyway 326(1) of FIG. 4. The keyway channel can be constructed from metal or other suitable material and can be positioned against the sideboards to create a block out of the keyway. Further, as can be appreciated from FIG. 7, the keyway channel 528 can be associated with a plurality of embedded keyway connections 704. In this case, the embedded keyway connections include keyway plates 706 secured to pieces of laterally oriented rebar 708. The laterally oriented rebar can extend part way or all the way across the form 502. The laterally oriented rebar of keyway plates 706 can also be tied to other laterally oriented rebar and/or longitudinally oriented rebar.

Briefly, the keyway plates 706 can be configured to be secured to a keyway of the adjacent module. For instance, the keyway plate can be configured to be fastened to hardware which can be fastened to corresponding hardware of the adjacent module. For example, the metal plate can be threaded to receive the hardware. Several keyway implementations are described below relative to FIGS. 9-18.

Example Process

The present concepts are now described relative to a process or technique for constructing modules for a given bridge system. The process is introduced generically and with reference to FIGS. 1-2 and 3-8 to provide specific examples.

The process can begin with designing the superstructure (such as superstructures 116 of FIGS. 1-2 and 316 of FIGS. 3-4). Superstructures can vary by the number of superstructures to employ per module and/or by type. For example, FIGS. 1-2 show an implementation with two generally parallel superstructures per module. FIGS. 3-8 show an implementation with one superstructure per module. The superstructure can also vary based upon the type of superstructure employed. For instance, the implementation of FIGS. 3-8 utilizes an “I-beam” girder type superstructure. Other implementations can utilize Wide Flange beams, Plate Girders, Steel Trusses or any other type of steel or iron support member. Once the type is decided, the number of modules can be determined and the number of superstructures per module can be determined. For instance, a single superstructure can be employed per module or multiple superstructures can be employed per module.

At this point, the road deck thickness and rebar reinforcing can be determined. Note that the present configuration is readily adaptable to constraints imposed by the travel route of the modules from the module manufacturing site to the bridge site. For example, module width can be varied to comply with gross vehicle weight road limits. For example, if a bridge design utilizing three modules exceeds the gross vehicle weight for one module per truck, each module can be narrowed and a larger number of modules employed. For example, five narrower modules may reduce module weight so that the gross vehicle weight is not exceeded. Another constraint on module weight can relate to the capacity and position of the crane (or other mechanism) utilized to set the modules at the bridge site.

The superstructure configuration can then be detailed in relation to the longitudinal joints enabled by the keyways 326 (FIG. 4). As can be appreciated from FIG. 5, in this implementation the keyways are formed by positioning keyway channel 528 against keyway form 514. The keyways can employ various elements for fastening to the adjacent keyway. In the illustrated implementation, the channel 528 includes embedded keyway connections 704. Keyways and embedded keyway connections are described below relative to FIGS. 9-18. The embedded keyway connections 704 can be configured to allow adjacent modules to be connected at the bridge site by pinning the connections through the holes in the steel connection, or by bolting. This feature allows for vertical alignment of the concrete deck, or other fastening solutions not available with existing technologies.

An erection plan can be developed that shows the layout of the erection sequence of the modules, the sequence of fastening the longitudinal joint connections (e.g., keyway connections) and any special instructions.

In one implementation an overall layout of the forming system can consist of the abutments 530, outrigger 608, support bracket 608, sheet material 516, side forms 510, end forms 512, keyway forms 514, blocking points 610, and/or blockouts 524. Note that the forming system is readily adaptable or customizable to particular bridge configurations. This aspect is in contrast to concrete pre-stress form systems that are limited to specific configurations.

The abutments 530 can be placed under the girder 320(1) at the bearing points. The abutments function to set the correct elevations and square the girder. The abutments can be made of tube steel or other suitable material.

Outrigger 606 includes diaphragm brace 602 and adjustable stand 604. The diaphragm brace 602 can be a girder or other type of structural material that is fastened to the girder 320(1) at a right angle. The adjustable stand 604 can be connected to the diaphragm brace 602. The adjustable stand can be adjusted to hold proper elevations and square the girder.

Support bracket 608 is attached to the girder 320(1) and functions to support the sheet material 516. In this case, the sheet material overlays support members 612. The support members 612 are supported by the support bracket 608 via the connector 610. Thus, the support bracket functions to hold the sheet material 516 at the correct slope and elevation. The sheet material 516 in turn serves as the base of the bridge deck 318(1). The sheet material 516 can also connect the side forms 510, end forms 512, and keyway forms 514. The side forms provide the finish edge of the concrete bridge deck. The side forms can have a ¾″ (or other dimension) chamfer on the top and bottom of the form. The keyway form interacts cooperatively with channel 528 to form the keyway in the road deck. The keyway can be thought of as a longitudinal region that is configured to receive hardware for connecting the module to an adjacent module.

In some implementations, the keyway is manifest as a longitudinal slot in the deck of the module, at or part way between, the upper and lower deck surfaces. The hardware can be directly secured to the concrete of the deck at the keyway (e.g., embedded in the concrete) or intermediaries, such as the plates described above can be secured to the concrete and the hardware can be secured to the intermediary. Some examples of keyway configurations are shown and described relative to FIGS. 9-18.

End forms 512 provide the finish edge at the ends of the bridge. In some cases, chamfer can be provided at the top of the form. For instance, a ¾″ (or other dimension) chamfer can be employed in some cases.

The blocking points 614 can be utilized to support the girder 320(1) in a desired configuration. For instance, the blocking points can be utilized to impart a camber in the girder. For example, in a case where two inches of camber are desired in a 100 ft girder, the blocking points can be employed at each end, and at 25 ft, 50 ft, and 75 ft. In such a case, the 25 ft and 75 ft blocking points could be blocked one inch higher than the end points, and the 50 ft (e.g., middle) blocking point could be blocked two inches higher than the end points. Of course, this is but one example of the length of the girder and the number, location, and relative height of the blocking points that can be utilized to establish the camber.

The following discussion relates to fabrication of the superstructure. The embedded keyway connections 704 can be constructed for later inclusion in the form 502. For instance, the keyway plate 706 can be secured to pieces of laterally oriented rebar 708. For example, the keyway plate 706 can be secured to two pieces of laterally oriented rebar 708 by cutting, punching, drilling, and/or welding rebar 708 (or other material) to the keyway plate 706. The embedded keyway connections 704 can be connected to the channel 528. The channel and keyway plates can then be attached to the keyway form 514. The keyway form can then be moved to the forming or casting area.

Rail connections 526 can be prepared. In one case, pipes or tubes can be secured to a plate to create the rail connections. In some implementations, the rail connections may be galvanized to resist degradation. The finished rail connections 526 can be moved to the forming or casting area.

The girder 320(1) can be stabilized by securing the girder to the abutment 530. In some cases the girder can be bolted to the abutment to stabilize the girder during fabrication. The abutment 530 and the blocking points 614 can be used to level the girder and/or the form and to set exact elevations at the bearing points during the concrete pour in the form.

The outriggers 606 can be positioned to provide stability to the girder 320(1) and form structure during the concrete pour.

Support brackets 608 can be bolted to the girder 320(1) after it is placed in the forming or casting area. The support brackets can provide the structural support required for the sheet material 516 of the form 502. In the illustrated example, the support brackets 608 support the sheet material 516 via the intervening connector 610 and support members 612. The support members 612 are supported by the support bracket 608 via the connector 610. Thus, the support bracket functions to hold the sheet material 516. Also, support brackets 608 can allow for any adjustments on the slope of the bridge deck (such as slope or crown associated with draining the bridge deck).

The following discussion relates to the forming process and serves to explain the interactions of the elements introduced above. The superstructure (in this case girder 320(1)) can be set utilizing the abutments 530, which are located at both ends of the structure, so the bearing points are at the same elevation. The girder 320(1) can be vertically leveled with the abutments 320(1). Blocking points 614 in the form of steel shims can be utilized between the abutments and the girder to instill a desired camber in the girder. The outriggers 606 can be attached to the girder. The outriggers can be adjusted to vertically level the superstructure between the abutments.

The support brackets 608 can be attached and the brackets 610 can be positioned on the support bracket. Elevations of the brackets support saddles can be set to hold the support members 612. In one case, the support brackets 608 can be manifest as Simpson-type connectors or gauge metal equivalents and the support members 612 can be manifest as two 2×6 structural lumber boards. The sheet material 516 in the form of plywood can be positioned on the support members and secured to the support members, such as with wood screws. Elevation of the form 502 can be fine tuned with the supports 608.

The depth of the bridge deck can be determined by the forms 502. Any concrete depth can be accommodated. The side form 510 can be set at the appropriate width, vertically level. The side form can be attached to the sheet material 516 (e.g., plywood) with screws. Keyway form 514 can be attached to the sheet material 516. Recall that in some configurations, the channel 528 and the embedded keyway connections 704 were pre-assembled onto the keyway form 514. If not, the channel 528 can be attached to the keyway form 514 and the embedded keyway connections 704 can be attached to the channel.

The end form 512 can be set at the appropriate location to define the length of the module 314(1). The end form can be vertically leveled and attached to the sheet material 516 (e.g., plywood) with screws and to the keyway form 514. The dimensions, edges, and shape of the module are now defined by the forms, the sheet material and the girder. These aspects can be readily inspected and changes made if necessary to maintain high tolerances. For instance, an individual form board may have a crown or bow that can be addressed or the form board can be replaced.

Elements within the forms can now be positioned before the pour. Rebar can be installed and spaced. In scenarios that involve a double layer of rebar, the bottom mat of rebar can be set and spaced as specified followed by the top mat.

The rail brackets 526 can be placed on the forms at the proper location, and secured to the sheet material 516 (e.g., plywood) with screws or bolts. The top of the brackets can be blocked, such as with tape to keep concrete from getting in.

Drip Edge can be formed by attaching a wood triangle to the top of the plywood along the finish edge of the bridge modules. Threaded inserts (for utility use) can be attached to the sheet material 516 (e.g., plywood) along one side of the finish edge of the bridge modules.

Completed forms can be filled with concrete 500. As the concrete cures, it bonds to the girder 320(1), such as by bonding to the anchor studs 520. After the concrete has cured to specifications, the side, end, and keyway forms can be stripped. Connectors 610 can be lowered on the brackets 608. The sheet material 516 (e.g., plywood) can be removed. Keyway hardware can be installed on the embedded keyway connections 704. The bridge deck concrete is now bonded to the girder and the rigidity of the concrete serves to maintain the camber of the girder.

Note that the present implementations do not require applying any type of force to the concrete, either during or after the pour. For instance, pre-stress concrete techniques utilize tension cables during the pour. These cables are then released after the concrete cures to create compressive forces on portions of the concrete. The response of the concrete to these compressive forces can vary from unit to unit and/or within a unit. For example, one unit may bow more overall from the stress than the next unit. In another example, one unit may bow generally uniformly along a length of the unit whereas another unit may bow more in some areas than in others. As such, attempts to align units to create a bridge can create bridge deck mismatches. Further, the present concepts can allow the bridge deck to have a uniform thickness across a module (e.g., along the xz-reference plane). In contrast pre-stressed concrete units require increasing the concrete thickness proximate to the tensioning cables and/or at certain deck regions.

Further still, in some of the present implementations, the distinction between the superstructure 316 and the bridge deck 318 are blurred in that the bridge deck 318(1) is bonded to the girder 320(1) and can provide structural strength and/or maintain camber of the girder (e.g., superstructure). As a result, a smaller superstructure can be utilized than would be the case where the bridge deck simply sits atop the superstructure. Stated another way, in the present implementations, the load bearing capacity of the modules is greater than the load bearing capacity of the superstructure taken in isolation plus the load bearing capacity of the bridge deck taken in isolation. With other technologies, the bridge deck has little or no load bearing capacity and is simply dead load that reduces the camber of the superstructure and the overall load bearing capacity of the superstructure.

FIG. 8 shows embedded keyway connections 704 and the keyway plates 706 on a portion of poured and stripped module 314(1). Keyway fasteners or hardware 802 can be connected to the keyway plates.

Example Keyways

FIGS. 9-18 illustrate several keyway implementations in greater detail. The implementations are explained relative to bridge decks 318(1) and 318(2) introduced relative to FIG. 4.

FIGS. 9-12 collectively relate to a first keyway implementation explained relative to modules 314(1) and 314(2) introduced relative to FIG. 4. In this case, concrete of bridge deck 318(1) is designated at 500(1) and concrete of bridge deck 318(2) is designated at 500(2). Keyway 326(1) is formed into concrete 500(1) and keyway 326(2) is formed into concrete 500(2). (Note that a dotted outline is provided to help define keyway 326(1), however, the dotted outline tends to create clutter on the drawing page so keyway 326(2) uses a more typical arrow that points to the general region of the keyway). In this case, the keyways are longitudinal blockouts (e.g., extending into and out of the drawing page (parallel to the y-reference axis). In this implementation, the keyways start at the upward facing surface (e.g. driving surface 304) of the concrete and extend part way through the concrete toward an opposing downward facing surface (e.g., bottom surface) 902. (Note that driving surface 304 and downward facing surface 902 apply to the entire bridge and not specific modules so no distinguishing suffix is employed on the designator). The keyways can include hardware configured to fasten the two keyways together. In this case, the hardware is manifest as “eye bolts” 904(1) and 904(2) that are embedded (dotted line) in concrete 500(1) and 500(2), respectively.

FIG. 10 shows a subsequent view where modules 314(1) and/or 314(2) have been roughly aligned (e.g., moved toward one another). (This can be accomplished by a crane connected to lifting lugs 702 (FIG. 7)). FIG. 11 shows the eye bolts 904(1) and 904(2) fastened with additional hardware. In this case, the additional hardware is manifest as a bolt 1102 that is oriented into the drawing page (e.g., parallel to the y-reference axis). A corresponding nut is obscured by the bolt head and the eye bolts. The bolt head is shown in dotted lines to allow the underlying eye bolts to be visualized. Any final alignment of the two modules can be accomplished with the bolt 1102. This implementation can allow for very precise alignment of the two modules (and for the precise alignment to be maintained).

FIG. 12 shows a subsequent view where the keyways 326(1) and 326(2) are filled with a curable material 1202, such as an epoxy grout. The curable material can serve several functions. First, the curable material can complete the driving surface 304. Second, the curable material can protect the hardware (e.g., eye bolts 904(1) and 904(2), bolt 1102 and the corresponding nut) from degradation, such as may be caused by water and/or road salts. Third, the curable material can lock the bolt and nut in place. Fourth, the curable material can contribute to the continuity and integrity of the bridge modules.

FIGS. 13-14 show a variation of the keyway described above relative to FIGS. 9-12. This variation is explained relative to keyway 326(1) of module 314(1). In this case, keyway 326(1) includes keyway plate 706 embedded in concrete 500(1). The keyway plate can be configured to be fastened to hardware for fastening the module to an adjacent module. In this implementation, the keyway plate 706 is threaded to receive hardware in the form of a threaded eyebolt 1302 as indicated by arrow 1304. This configuration allows keyways to easily be formed without hardware protruding through the keyway form. The remaining functionality is similar to that described above relative to FIG. 9-12.

FIGS. 15-16 and 17-18 show two keyway implementations similar to those shown in FIG. 7.

FIG. 15 shows keyway elements from two adjacent modules in isolation (e.g., without the modules). FIG. 16 shows the same elements embedded in concrete of their respective modules 314(1) and 314(2). Note that the orientation of FIGS. 15 and 16 is not the same. FIG. 15 is a view taken above the modules (e.g., parallel to the z-reference axis). FIG. 16 is a sectional view taken laterally through the modules (e.g., parallel to the y-reference axis). In this case, the elements include embedded keyway connections 704(1) and 704(2). As mentioned above relative to FIG. 7, in this implementation the embedded keyway connections include keyway plates 706 secured to pieces of laterally oriented rebar 708. Further, each keyway plate is fastened to hardware in the form of an angle clip 1502 via a bolt 1504. Adjacent modules can be fastened together by fastening the angle clips with another bolt 1506 that can be lowered vertically into the keyway from the deck surface 304 and fastened to a corresponding nut 1508. Further, tightening the bolt 1506 and nut 1508 forces angle clips 1502(1) and 1502(2) towards one another in the vertical direction (e.g., parallel to the z-reference axis). This action serves to raise module 314(2) relative to module 314(1). Thus, tightening the bolt and nut provides a mechanism for easily and precisely vertically aligning modules 314(1) and 314(2) to ensure that driving surface 304 is uniform across the modules (e.g., when viewed parallel to the x-reference axis). Stated another way, this longitudinal keyway implementation is configured to facilitate vertical adjustment of the bridge module 314(1) relative to an adjacent bridge module 314(2).

FIGS. 17-18 are similar to FIGS. 15-16 except that the clips 1502(1) and 1502(2) are rotated 90 degrees so that the clips are oriented horizontally from one another (e.g., the clips are facing one another rather than stacked vertically one above the other as in FIGS. 15-16). In this case, the clips 1502(1) and 1502(2) are oriented so that a fastener 1702 can pass through them in a horizontal orientation rather than a vertical orientation. A bolt may be used as a fastener for a single pair of embedded keyway connections. Alternatively, a long fastener, such as a bolt or a piece of rebar may be passed through and fasten multiple pairs of embedded keyway connections. Among other functions, the horizontally oriented clips provide a mechanism for structurally inter-connecting adjacent modules 314(1) and 314(2). Of course, other types of hardware are contemplated and encompassed by the present concepts.

Recall that in this implementation the keyway plates 706 are threaded to be fastened to the angle clip 1502 via bolt 1504. Thus, the angle clip can be oriented as desired during the fastening process. For instance, some implementations can utilize both vertically oriented clips and horizontally oriented clips to interconnect the adjacent modules 314(1) and 314(2). For example, in one case involving a module length of approximately 92 feet, 23 keyway plates and clips can be utilized per module. In this case, keyway plates are positioned about six feet from each end of the modules. The remaining keyway plates are interposed between these two end keyway plates at about five foot spacing. A majority of the clips can be oriented horizontally with a remainder oriented vertically. For instance, in one example, starting at one end of the module, the second, seventh, twelfth, seventeenth, and twenty-second clips can be oriented vertically and the remainder oriented horizontally. When the modules are positioned adjacent one another, the horizontally oriented clips of the two modules can be fastened together to structurally interconnect the modules as described relative to FIGS. 17-18. Any relative height adjustments between individual points along the length of the two modules can be controlled using individual vertically oriented clips as described above relative to FIGS. 15-16. Further, clips can be switched from horizontal to vertical to address the conditions encountered simply by loosening the bolt of the clip, rotating the clip and retightening. (Of course, the length of the above modules and the number and orientation of the clips is provided for purposes of explanation. Other configurations are contemplated and encompassed by the present concepts).

Note that in this implementation, the keyways 326(1) and 326(2) include a blockout that is interposed in the concrete between the upward facing surface (e.g. driving surface 304) and the opposing downward facing surface 902. The keyways collectively create a space for the hardware and for workers to install the hardware through the bridge deck's driving surface 304. Once the adjacent modules are fastened at this ‘collective keyway’, grout or other material can be used to fill in the keyway. If a gap in the keyway at the downward facing surface 902 is large enough to allow excessive grout to escape, a resilient material such as a rope can be used to block the opening until the grout hardens.

To summarize, the keyways 326(1) and 326(2) can be filled with any material that is manipulatable and that cures into a harder state. Concrete can be used, but faster curing materials may be desired to speed up opening the bridge to traffic. For instance, various grouts, such as epoxy based grouts can be utilized. Once cured, the road deck may be grooved for traction purposes if desired.

As mentioned above, the present keyway concepts allow precise deck alignment of adjacent modules by adjusting the keyway connections. Once the desired orientations are achieved and the keyways are grouted (or concurrently to the orienting and grouting), diaphragm braces 602 of adjacent modules can be secured to provide the cross-bracing 324(1) (see FIGS. 4-8). In this case, the opposing faces of the diaphragm braces are bolted together, but other securing mechanisms can be utilized. Thus, the present implementations can provide modules that are readily, quickly, and precisely fastened on-site via the longitudinal keyways. The bridge can be used as soon as the grout cures and the diaphragm braces are connected. The on-site assembly time can be minutes or hours before use with the present concepts. In contrast, traditional site poured concrete decks have cure times of 28 days, plus the time to form, place and tie rebar, pour and finish the concrete deck, and strip the forms, all of which are performed in place at the bridge site with traditional technologies.

In summary, the present implementations can bond a pourable bridge deck to a steel superstructure to obtain properties more advantageous than can be obtained by either element in isolation. Stated another way, in some of the present implementations, the distinction between the superstructure and the bridge deck are blurred in that the bridge deck can provide structural strength and/or maintain camber of the superstructure. As a result, a smaller superstructure can be utilized than would be the case where the bridge deck simply sits atop the superstructure as dead load weight. Further, the present keyway concepts are more efficient than link slabs employed with some existing techniques.

The present keyways can allow full concrete deck width on the modules which alleviates the need for field forming, placing and tying rebar, field pouring concrete slabs, tying the modules together, and removing the forms after the concrete is cured. The keyways allow for quick and precise fastening of adjacent modules compared to waiting for field poured slabs to connect adjacent modules or field welding each connection.

Further, the present techniques can support the superstructure during bonding of the bridge deck to the superstructure to achieve true camber in the finished modules. Traditional technologies require analyzing the weight of the precast panels and calculating the required camber for the weight of the concrete deck. A prediction is made to produce the camber with a given tension force. Often the actual cambers produced are different. If the camber is different on each module it effects how the concrete decks line up in the field. Further, traditional techniques rely upon applying large counterweights to a slab to vertically align the slab with the adjacent slab if the cambers are different. The slabs are then welded together and the counterweight is released. This process subjects the welds to high stress forces once the counterweights are removed.

Instead the present implementations can achieve precise cambers from bonding the road surface to the superstructure to maintain the camber set during the forming process of the module. Any vertical adjustments are readily achieved with the vertical orientation of the keyways described above relative to FIGS. 15-18.

CONCLUSION

Although techniques, methods, devices, systems, etc., pertaining to modular bridge implementations are described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described. Rather, the specific features and acts are disclosed as exemplary forms of implementing the claimed methods, devices, systems, etc. 

1. A bridge module, comprising: a concrete deck; and, a steel superstructure that is embedded in the concrete deck, wherein the concrete deck contributes to maintaining a longitudinal camber of the superstructure and wherein the concrete deck includes at least one longitudinal keyway configured to be fastened to the bridge module and to another adjacent bridge module.
 2. The bridge module of claim 1, wherein the steel superstructure comprises a single steel beam or a single steel truss.
 3. The bridge module of claim 1, wherein the steel superstructure comprises multiple parallel steel beams or multiple parallel steel trusses.
 4. The bridge module of claim 1, wherein the concrete deck completely maintains the longitudinal camber of the superstructure that existed at the time the concrete deck was poured around the superstructure.
 5. The bridge module of claim 1, wherein the concrete deck is bonded to the superstructure in a manner that increases a load bearing capacity of the bridge module when compared to the superstructure alone.
 6. The bridge module of claim 1, wherein the at least one longitudinal keyway comprises a pair of longitudinal keyways on opposing sides of the concrete deck.
 7. The bridge module of claim 1, wherein the at least one longitudinal keyway comprises a single longitudinal keyway on one side of the concrete deck and the bridge module further comprises a guard rail on an opposing side of the concrete deck.
 8. The bridge module of claim 1, wherein the at least one longitudinal keyway includes hardware configured to secure the bridge module to the adjacent bridge module.
 9. The bridge module of claim 1, wherein the at least one longitudinal keyway includes mounting plates configured to receive hardware configured to secure the bridge module to corresponding hardware of the adjacent bridge module.
 10. The bridge module of claim 9, wherein a first set of the hardware is configured to allow vertical adjustment of the bridge module relative to the adjacent bridge module, and wherein a second set of the hardware is configured to structurally interconnect the module and the adjacent module.
 11. A bridge comprising the bridge module of claim 1 attached to the another bridge module along an individual longitudinal keyway.
 12. A bridge module that is transportable in a fully assembled configuration and that includes a steel superstructure and a concrete bridge deck.
 13. The bridge module of claim 12, wherein the bridge module is a width of a lane or is less than the width of the lane.
 14. The bridge module of claim 12, wherein the bridge module is configured to be fastened to other bridge modules to supply an overall bridge width.
 15. The bridge module of claim 12, wherein the bridge module has a length that is equal to or greater than a bridge span.
 16. The bridge module of claim 12, wherein the bridge module includes a longitudinal keyway that is configured to facilitate vertical adjustment of the bridge module relative to an adjacent bridge module.
 17. The bridge module of claim 12, wherein the bridge module includes a steel guard rail or barricade.
 18. The bridge module of claim 12, wherein at least some of the steel superstructure is embedded in the concrete bridge deck.
 19. The bridge module of claim 18, wherein the steel superstructure includes structures configured to increase bonding between the steel superstructure and the concrete bridge deck.
 20. A bridge comprising multiple parallel longitudinal modules, wherein an individual module comprises a steel superstructure embedded in a concrete deck that includes a longitudinal keyway and wherein the concrete deck serves to maintain a longitudinal camber of the steel superstructure rather than diminishing the longitudinal camber, and wherein adjacent parallel longitudinal modules are bolted together at adjacent opposing longitudinal keyways. 